TS08P 8-Channel Self Calibration Capacitive Touch Sensor SPECIFICATION...

SPECIFICATION V1.4

TS08P

8-Channel Self Calibration Capacitive Touch Sensor

July 2008 ADSemiconductor

Confidential

ADSemiconductor®

TS08P (8-CH Auto Sensitivity Calibration Capacitive Touch Sensor)

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1 Specification

1.1 General Feature

8-Channel capacitive sensor with auto sensitivity calibration

Selectable output operation mode (single output /multi output / dual single output)

Selectable output level (active high / active low / analog voltage output)

Uniformly adjustable 9 step sensitivity

3 Step internal calibration speed selections

Sync function for parallel operation

5 SYNC pins for various option selections

Almost no external component needed

Open-drain digital output

Low current consumption

Embedded common and normal noise elimination circuit

RoHS compliant 24QSOP and 24QFN package

1.2 Application

Home application

Membrane switch replacement

Sealed control panels, keypads

Door key-lock matrix application

Touch screen replacement application

1.3 Package (24QSOP/24QFN)

※ Drawings not to scale

24QSOP 24QFN

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2 Pin Description

2.1 24QFN package

Pin

Number Name I/O Description Protection

1 CS4 Analog Input CH4 capacitive sensor input VDD/GND

2 SYNC1 Digital Input

/Output

Sensitivity selection input 1 (Note 1)

Sync pulse input /output 1 VDD/GND






/Output



8 DUMMY - No Connection (Note 2) VDD/GND

9 VSS Ground Supply ground VDD


/Output

Output level selection input (Note 3)



/Output

Internal calibration speed selection

input (Note 4)

Sync pulse input /output 5

VDD/GND

12 OUT1 Digital Output

/Analog Output

CH1 parallel output (Open drain)

Ch1, 2, 3, 4 analog output VDD/GND

13 OUT2 Digital Output CH2 parallel output (Open drain) VDD/GND







/Analog Output




/Output

Output mode selection input (Note 5)


21 VDD Power Power (2.5V~5.0V) GND




Note 1 : Refer to 6.3.2 Sensitivity selections.

Note 2 : DUMMY pin should be no connection. Note 3 : Refer to 6.3.4 Output level selections.

Note 4 : Refer to 6.3.5 Internal calibration speed selections.

Note 5 : Refer to 6.3.3 Output mode selections.

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2.2 24QSOP package

Pin

Number Name I/O Description Protection





/Output



5 DUMMY - No Connection (Note 2) VDD/GND

6 VSS Ground Supply ground VDD


/Output

Output level selection input (Note 3)



/Output

Internal calibration speed selection

input (Note 4)

Sync pulse input /output 5

VDD/GND


/Analog Output










/Analog Output




/Output

Output mode selection input (Note 5)


18 VDD Power Power (2.5V~5.0V) GND






/Output




Note 1 : Refer to 6.3.2 Sensitivity selections.

Note 2 : DUMMY pin should be no connection. Note 3 : Refer to 6.3.4 Output level selections.

Note 4 : Refer to 6.3.5 Internal calibration speed selections.

Note 5 : Refer to 6.3.3 Output mode selections.

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3 Absolute Maximum Rating Battery supply voltage 5.5V

Maximum voltage on any pin VDD+0.3

Maximum current on any PAD 100mA

Power Dissipation 800mW

Storage Temperature -50 ~ 150

Operating Temperature -20 ~ 75

Junction Temperature 150

Note 6: Unless any other command is noted, all above are operated in normal temperature.

4 ESD & Latch-up Characteristics

4.1 ESD Characteristics

Mode Polarity Max Reference

H.B.M Pos / Neg

8000V VDD

8000V VSS

8000V P to P

M.M Pos / Neg

500V VDD

500V VSS

500V P to P

C.D.M Pos / Neg 500V

DIRECT 800V

4.2 Latch-up Characteristics

Mode Polarity Max Test Step

I Test Positive 200mA

25mA Negative -200mA

V supply over 5.0V Positive 8.0V 1.0V

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5 Electrical Characteristics (Preliminary)

VDD=3.3V, (Unless otherwise noted), TA = 25

Characteristics Symbol Test Condition Min Typ Max Units

Operating supply

voltage VDD 2.5 3.3 5.0 V

Current consumption IDD

VDD= 3.3V

Slow calibration speed - 60 100

Normal calibration speed - 90 140

Fast calibration speed - 130 210

VDD= 5.0V

Slow calibration speed - 80 130

Normal calibration speed - 110 180

Fast calibration speed - 170 250

Internal reset criterion

VDD voltage VDD_RST TA = 25 - - 0.3∙VDD V

Output maximum sink

current IOUT TA = 25 - - 4.0

Minimum detective

capacitance difference ΔCMIN 0.1 - -

Output impedance

(open drain) Zo

ΔC > ΔCMIN - 12 - Ω

ΔC < ΔCMIN - 30M -

Self calibration time

after system reset TCAL

Slow calibration speed - 100 -

ms Normal calibration speed - 80 -

Fast calibration speed - 60 -

Note 7: The sensitivity can be decreased with higher parallel capacitance of CS pin including

parasitic capacitance made by neighbor GND or other pattern.

Note 8: The series resistor(under 1kΩ) of CS can be used in noisy condition to avoid mal-

function from external surge and ESD.

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6 TS08P Implementation

6.1 Typical current consumption

TS08P uses internal bias circuit, so internal clock frequency and current consumption is fixed

and no external bias circuit is needed. TS08P has three step optional calibrations speed. Faster

calibration speed needs more current consumption than slower calibration speed. The typical

current consumption curve of TS08P is represented in accordance with VDD voltage as below.

Internal bias circuit can make the circuit design simple and reduce external components.

0

20

40

60

80

100

120

140

160

180

2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5VDD [V]

IDD [uA]

Fast

Normal

Slow

Typical current consumption curve of TS08P

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6.2 CS implementation

TS08P has 9 step selections of sensitivity and internal protection circuit so external components

of CS pins such as series resistor or parallel capacitor isn’t necessary. The parallel parasitic

capacitance of CS pins caused by touch line, touch pad and neighbor GND or other pattern

may affect sensitivity. The sensitivity will be decreased when bigger parallel parasitic

capacitance of CS pin is added.

Parallel capacitor (CS1~S8) of CS pin is useful in case of detail sensitivity mediation is required

such as for complementation sensitivity difference between channels. Same as above parallel

parasitic capacitance, sensitivity will be decreased when a big value of parallel capacitor

(CS1~S8) is used. Under 50pF capacitor can be used as sensitivity meditation capacitor and a

few pF is usually used. The RS, serial connection resistor of CS pins, may be used to avoid

mal-function from external surge and ESD. (It might be optional.) From 200Ω to 1kΩ is

recommended for RS. Refer to below CS pins application figure.

The TS08P has eight independent touch sensor input from CS1 to CS8. The internal touch

decision process of each channel is separated from each other. Therefore eight channel touch

key board application can be designed by using only one TS08P without coupling problem.

The size and shape of PAD might have influence on the sensitivity. The sensitivity will be optimal

when the size of PAD is approximately an half of the first knuckle (it’s about 10 ｘ 7 ). The

connection line of CS to touch PAD is recommended to be routed as short as possible to

prevent from abnormal touch detect caused by connection line.

CS8 << Touch PAD8

CS8

RS8

CS1 <<

CS1

RS1

Touch PAD1

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6.3 SYNC implementation

The TS08P has five SYNC pins to make it possible to operate with many optional functions such

as SYNCTM

function, sensitivity selections, output mode selection, output level selection, and

calibration speed selection. No external component is used for above selections.

The determination of SYNC pins connection of TS08P is accomplished in initial operation

periods. Therefore changing connection of SYNC pin after initial operation period cannot affect

the optional function selection.

6.3.1 SYNCTM function

For SYNCTM

function, all SYNC pins (form SYNC1 to SYNC5) have same function. So, at least,

one of five SYNC pins operates as SYNCTM

function, TS08P can be operated with other TS08P

or TSxx series without interfering with each other. Inside of TS08P, there is internal oscillator for

SYNC pulse so no external component is used for SYNCTM

function. Simply, it is needed to

connect SYNC pin to other SYNC pin of TS08P or TSxx series for using SYNCTM

function. For

proper SYNCTM

function, less five other TS08P or TSxx series can be connected with.

6.3.2 Sensitivity selections

SYNC1 and SYNC2 pin of TS08P can be used as sensitivity selection pin. Both of two SYNC

pins have three methods of connection. Open connection (N.C., SYNC connection), connection

to GND, and connection to VDD are these methods. As below table, TS08P has 9 step

sensitivity selections. When SYNC1 pin or SYNC 2 pin has no connection to GND or VDD, that

SYNC pin may be simultaneously used for SYNCTM

function.

Sensitivity level (thickness [mm] of proper poly-carbonate insulator) of each sensitivity selection

SYNC1

SYNC2 Connect to VDD Connect to GND

N.C.

(SYNC connection)

Connect to GND 15.0 13.0 11.0

N.C. (SYNC connection) 9.0 7.5 6.0

Connect to VDD 5.0 4.0 3.0

Note 9: The size of touch PAD is 10 ｘ 7 used.

Note 10: Above proper thickness is reliable but it can be changed by insulator material and

application.

SYNC <<

SYNC << 1

st TS08P

2nd

TS08P or TS**

SYNC << 5

th TS08P or TS**

SYNC pulse

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6.3.3 Output mode selections

SYNC3 pin of TS08P is output mode selection input pin. SYNC3 also has three connections,

such as open connection (N.C., SYNC connection), connection to GND, and connection to VDD.

The output mode of each connection is such as below table. When SYNC3 pin has no

connection to GND or VDD and TS08P operates as dual-single output mode, SYNC3 pin may

be simultaneously used for SYNCTM

function.

Output mode of each SYNC3 connections

SYNC3 connection Connect to VDD Connect to GND N.C.

(SYNC connection)

Output mode Single output Multi-output Dual-single output

When SYNC3 is connected to VDD and TS08P operates as single output mode, the one output

that is detected fastest is appeared. So application PCB composed very near touch pads is

possible to operate without confusion of neighborhood touch. When SYNC3 is open and TS08P

operates as dual-single output mode, the one output that is detected fastest among CS1~CS4

and the one output that is detected fastest among CS5~CS8 is appeared independently. At

multi-output mode, all output of TS08P can be appeared.

6.3.4 Output level selections

SYNC4 pin of TS08P is output level selection input pin. SYNC4 also has three connections, such

as open connection (N.C., SYNC connection), connection to GND, and connection to VDD. The

output level of each connection is such as below table. When SYNC4 pin has no connection to

GND or VDD and TS08P operates as active low output level, SYNC4 pin may be simultaneously

used for SYNCTM

function.

Output level of each SYNC4 connections


(SYNC connection)

Output level Active high Analog output Active low

When active high is selected TS08P outputs are low in normal state and become high in touch

detect state. When TS08P is used as active low output, the level of normal state is high and that

of touch detect is low.

TS08P has internal analog output circuit and all the output of CS can be express as analog

voltage value using only two output ports (OUT1, OUT8). Analog voltage output values for from

OUT1 to OUT4 are expressed by OUT1 pin, and for from OUT5 to OUT8 are expressed by OUT8

pin. Analog voltage output values for each output in analog output mode are as below

equations. In this analog output mode, other parallel outputs (OUT2~OUT7) have each states

digital output (High or low) and output mode is selected by SYNC3 connection. But, even if

output mode is multi-output, OUT1 (OUT8) has only one analog output value of lower voltage.

No other external component is needed in this analog output mode.

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Analog output circuit of TS08P

Analog OUT1 : [V]VR

V DD_CSOUT 01

011

Analog OUT2 : [V]VVRR

RV DDDD_CSOUT

306.0

21

221

Analog OUT3 : [V]VVRRR

RRV DDDD_CSOUT

5.0

321

3231

Analog OUT4 : [V]VVRRRR

RRRV DDDD_CSOUT

706.0

4321

43241

Analog OUT5 : [V]VVRRRR

RRRV DDDD_CSOUT

706.0

5678

56741

Analog OUT6 : [V]VVRRR

RRV DDDD_CSOUT

5.0

678

6731

Analog OUT7 : [V]VVRR

RV DDDD_CSOUT

306.0

78

721

Analog OUT8 : [V]VR

V DD_CSOUT 08

011

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The OUTPUT pins have an open drain structure. For this reason, in the case of using TS08P as

active high or active low the connection of pull-up resistor ROUT is required between OUTPUT

and VDD. The maximum output sink current is 4mA, so over a few kΩ must be used as ROUT.

Normally 10kΩ is used as ROUT.

OUT1

ROUT1

OUTPUT1

VDD

OUT2

OUT3

OUT4

OUT5

OUT6

OUT7

OUT8

ROUT2

OUTPUT2

OUTPUT3

OUTPUT4

OUTPUT5

OUTPUT6

OUTPUT7

OUTPUT8

ROUT3

ROUT4

ROUT5

ROUT6

ROUT7

ROUT8

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6.3.5 Internal calibration speed selections

SYNC5 pin of TS08P is calibration selection input pin. SYNC5 also has three connections, such

as open connection (N.C., SYNC connection), connection to GND, and connection to VDD. The

calibration speed of each connection is such as below table. When SYNC5 pin has no

connection to GND or VDD and TS08P operates as normal calibration speed, SYNC5 pin may

be simultaneously used for SYNCTM

function.

Calibration speed of each SYNC5 connections


(SYNC connection)

Calibration speed Fast Slow Normal

It is recommendable to use fast calibration speed at various environmental conditions. Current

consumption is increased when faster calibration speed is used.(refer 6.1 Current consumption)

6.4 Internal reset operation

The TS08P has stable internal reset circuit to offer reset pulse to digital block. The supply

voltage for a system start or restart should be under 0.3∙VDD of normal operation VDD. No

external components required for TS08P power reset, that helps simple circuit design and to

realize the low cost application.

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7 Recommended Circuit Diagram

TS08P

16

8

4

7 9 12

23

56

11

10

1413

15

11718

19

20

21

22

23

24

OUT5

DU

MM

Y

CS6

SY

NC

2

VS

S

OU

T1

SYNC1CS5

CS7CS8

SY

NC

5S

YN

C4

OUT3OUT2

OUT4

CS4OUT6OUT7

OU

T8

SY

NC

3V

DD

CS

1C

S2

CS

3

R710k

R410k

OUT8Touch Pad4

SYNC1 ~ SYNC5

Touch Pad1

R810k

OUT1

Touch Pad7

SY

NC

2

R610k

Touch Pad2

OUT7

N.C

0

Touch Pad5

0

N.C. or to other TSxxseries SYNC pins

OUT6SYNC1

VDD

R310k

OUT5

R210k

R510k

Touch Pad8

Touch Pad3

VDD

SY

NC

3

R110k

OUT4S

YN

C5

CVDD1u

OUT2OUT3

0

Touch Pad6S

YN

C4

TS08P (24QFN) Application Example Circuit

TS08P (24QSOP) Application Example Circuit

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TS08P is reset by internal reset circuit. VDD voltage rising time should be shorter than

100msec for proper operation.

The VDD periodic voltage ripple over 50mV and the ripple frequency is lower than 10 kHz can

cause wrong sensitivity calibration. To prevent above problem, power (VDD, GND) line of touch

circuit should be separated from other circuit. Especially LED driver power line or digital

switching circuit power line certainly should be treated to be separated from touch circuit.

The CS patterns also should be routed as short as possible and the width of line might be

about 0.25mm.

Parallel capacitor of CS pin could be useful in case detail sensitivity mediation is required

such as for complementation sensitivity difference between channels.

Serial connection resistor of CS pins may be used to avoid mal-function from external

surge and ESD.

The capacitor that is between VDD and GND is an obligation. It should be located as close as

possible from TS08P.

The CS pattern routing should be formed by bottom metal (opposite metal of touch PAD).

The empty space of PCB must be filled with GND pattern to strengthen GND pattern and to

prevent external noise from interfere with sensing frequency.

The sensitivity can be changed by connection of SYNC1 and SYNC2.

(See 6.3.2 Sensitivity selections)

Output modes (single / multi / dual single) can be changed by connection of SYNC3.

(See 6.3.3 Sensitivity selections)

Output level in each state is selectable by connection of SYNC4.

(See 6.3.4 Output level selections)

The OUT1 ~ OUT8 are open drain output ports. Therefore, in the case of active high output or

active low output, the pull-up resistor should be needed as above figure. But it is not necessary

to use any pull-up resistor in analog output mode. (See 6.3.4 Output level selections)

Internal sensitivity calibration speed can be changed by connection of SYNC5. It is

recommendable to use fast calibration speed at various environmental conditions.

(See 6.3.5 internal calibration speed selections)

At least, one of five SYNC pins has SYNC connection, TS08P can be operated with other

TS08P or TSxx series without interfering with each other. (See 6.3.1 SYNCTM

function) Unused CS pins may be connected to GND for stable operation.

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7.1 Example – Power Line Split Strategy PCB Layout

A. Not split power Line (Bad power line design)

The noise that is generated by AC load or relay can be loaded at 5V power line.

A big inductance might be appeared in case of the connection line between main board and

display board is too long, moreover the voltage ripple could be generated by LED (LCD)

display driver at VDD (5V).

B. Split power Line (One 5V regulator used) – Recommended

C. Split power Line (Separated 5V regulator used) – Strongly recommended

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8 MECHANICAL DRAWING

8.1 Mechanical Drawing (24 QFN)

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8.2 Mechanical Drawing (24 QSOP)

Ref. : 24QSOP has 24 leads

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9 MARKING DESCRIPTION

Device Code : T S 0 8 P

Weekly Code : YY ZZ

Manufacturing Year

Manufacturing Week

Type of version Channel Number Touch Switch Group

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NOTES:

LIFE SUPPORT POLICY AD SEMICONDUCTOR’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL COUNSEL OF AD SEMICONDUCTOR CORPORATION

The ADS logo is a registered trademark of ADSemiconductor

2006 ADSemiconductor – All Rights Reserved

www.adsemicon.com

www.adsemicon.co.kr

TS08P 8-Channel Self Calibration Capacitive Touch Sensor SPECIFICATION...

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